let a=7777;
let b =5;

console.log(a+b);

console.log("hello world");

 
// global 全局对象

// document.getElementById();

// Nodejs 环境中没有window对象
// console.log(window); //window is not defined

console.log(global); //Object [global]

setTimeout(() => {
    console.log(123);
}, 100);

